Changing to Doug's D453s

Hello Guys,

Looking for some input regarding headers. “I know, I know”, I’m replacing my 318 with a 360/408 in the 74 Duster and it has PWR Steering and auto 727 with column shift. It currently has a set of the generic or cheapo “????” headers. You know the ones that all look the same whether their hooker’s, headman’s. etc. you know the ones that hang below the steering components and get banged up all the time. Anyway, I was thinking about switching to Doug’s D453s and started to wonder if I would have to modify the existing exhaust to match up with the collector. Has anyone replaced one of these cheap set of headers with Doug’s and if so what additional changes did you have to make? By the way, the car was a slant 6 car and has the motor mount kit, not sure if it matters, thanks